Livestock Poisoning Plants: Identification and its Veterinary Importance in Afar Region of Ethiopia
Angesom H. Desta1, *
Identifiers and Pagination:Year: 2019
First Page: 107
Last Page: 115
Publisher Id: TOASJ-13-107
Article History:Received Date: 19/03/2019
Revision Received Date: 17/06/2019
Acceptance Date: 19/07/2019
Electronic publication date: 30/09/2019
Collection year: 2019
open-access license: This is an open access article distributed under the terms of the Creative Commons Attribution 4.0 International Public License (CC-BY 4.0), a copy of which is available at: (https://creativecommons.org/licenses/by/4.0/legalcode). This license permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Plants are the major source of feed and have vital nutritious importance to animals; however, they also comprise a large variety of poisons known.
A study was conducted to identify potential poisonous plants to domestic animals and its veterinary importance in selected districts of Afar region, Northeast Ethiopia.
Questionnaire survey and key informants interview were done with a total of 245 respondents and plant samples were taken for identification.
A total of 21 plants were identified and documented to have a poisonous effect on livestock. The poisonous plants frequently complained by the respondents were Capparis tomentosa, Prosopis juliflora, Parthenium hysterophorus, Lantana camara, Acacia absynica, Sorghum bicolar, Datura stramonium, Plantago lanceolata, Pteridium aquilinum and Solanum incanum. The majorly described predisposing factors for the occurrence of plant poisoning were feed shortage, nutritional deficiency and excessive consumption. The common poisoning seasons indicated were at the end of rainy season and during drought time. The plant parts that caused poisoning were leaves of plants. This study also revealed that bloating and other GIT disturbances, salivation, bloody urine and in appetance were among the frequently manifested signs in poisoned livestock. Moreover, this study showed that caprine and ovine followed by camels and bovine were the most frequently poisoned animals.
Phytopoisoning is commonly occurring and challenging health of livestock in the study area. Hence, proper range management should be practiced to decrease the danger of plant poisoning to animals and all concerned bodies should collaborate on pasture and water development programs to minimize the risk of enforced consumption of livestock on poisonous plants due to feed shortage.
Plants are the major source of feed for herbivorous animals and also used for the treatment of many diseases. Moreover, plants have vital nutritious importance to animals and providing the normal atmospheric oxygen. As animals majorly feed on plants and these plants comprise a large variety of poisons known , poisoning in animals consuming these plants is inevitable. Poisonous plants produce their toxic effects after being ingested and/or absorbed by animals, which include physical upset, loss of productivity and death. A variety of poisonous plants have caused extensive losses to the livestock industry in many parts of the world mainly east Africa including Ethiopia .
The possibility of founding poisonous plants in hay and forage poses a serious risk to livestock and other animals. There are several contributing factors, which facilitate the occurrence of animal poisoning. Different sensitive species of animals can ingest or exposed to a poisonous plant at normal conditions. It is also more likely to occur in animals which have been moved from one part of the country to another. Sudden onset of disease in a group of animals is the most obvious case among the many indications of plant poisonings .
Factors such as route of absorption, dose, physical and chemical nature of the poison, frequency of exposure, species, body size, sex, and general health status of the animal may influence the action of poisonous substances. In addition, chemical factors such as particle size, solubility, toxicity, absorption and excretion rate, affinity for body tissues or fluids, interaction with other drugs, and lacking development of metabolic pathway can have an impact on its occurrence. Liver or kidney insufficiency may enhance toxicity due to poor metabolism or slow excretion of toxicants. Alteration in gastrointestinal pH can change the ionization of drug or chemicals and influence their absorption; presence or absence of food in the stomach affects the toxicity of certain compounds .
Plant poisoning of livestock can be diagnosed based on history, clinical syndrome observed, post mortem lesions, evidence of plant grazing and/or browsing, and remains of poisonous plants in the gastro intestinal tract. If poison principle of the poisonous plants is known, confirmatory laboratory tests can be done . Good pasture management such as keeping the desirable forage species productive throughout the grazing season reduces the possibility of animals grazing on poisonous plants. In this case, most poisonous weeds and cultivated plants can be controlled. It may be practical to simply fence off infested areas so that animals do not have access to particularly hazardous weeds. This is one of the most important steps in preventing animal suffering or loss from poisonous plants. Other alternative methods of controlling poisonous weeds are to spray them with approved herbicides and physically or mechanically remove the poisonous plants .
Poisonous plants affecting both large and small animals are a major concern for the practicing veterinarian and livestock producer in every country. In countries with higher plant biodiversity, the problem of plant poisoning to livestock may be greater. Plant biodiversity in Ethiopia is very high, as there are about 7,000 species of vascular plants in which some of it could be poisonous .
Plant poisoning in livestock can occur due to either accidental ingestion along with grass or obstinate consumption. Animals can consume poisonous plants when pasture is dry while most poisonous plants remain green all throughout the year . Newly imported or animals migrated from other areas could be at higher risk because they are unfamiliar with the strange ingestion of their fresh surrounding .
Overgrazing of pastures and ranges probably the greatest factor in causing losses from poisonous plants. The danger of overgrazing is always greatly increased in periods of moisture deficiencies that reduce forage production. However, plant poisoning essentially is a local problem occurring in areas where poisonous plants may form a large proportion of the herbage species available to grazing animals. Poisonous plants are often naturally refused by animals due to their repulsive smell or irritant juices and are eaten only when other herbage pastures is scarce . Some plants may have the potential to penetrate skin of animals and introduce a poisonous chemical and causes an immediate burning sensation of the skin .
Among the factors that expose the livestock to the poisonous plants; shortage of feed, nutritional deficiency and sudden exposure were the major problems [1, 9]. Feed shortage can force animals to browse perennial shrubs and bushes while most of these perennial plants have been known to contain toxic secondary metabolites . These plant poisoning cause health problems in livestock with huge economic loss to the pastoralists due to production loss, morbidity and mortality of their animals. Furthermore, it is not customary among local veterinarians to write plant poisoning case reports, thus most of the plant poisonings that occur in the pastoral areas of Ethiopia are not well documented in the literature. Hence, it is imperative to bring the attention of professionals to the effects of poisonous plants on animal health and productivity . Therefore, this study was conducted to fill this gap by identifying the potential poisonous plants to domestic animals and its veterinary importance in selected districts of Afar region, Northeast Ethiopia.
2. MATERIALS AND METHODS
2.1. Study Areas
Afar regional state is located in the Great Rift Valley, comprising semi-arid range land in northeastern Ethiopia. According to regional estimates, the livestock population of Afar is about 10.12 million. The livestock populations found in the region are 2,318,220 cattle, 2,499,640 sheep, 4,444,290 goats and 859,580 camels. The Afar Regional State has five administrative zones, which are further subdivided into 32 districts. Pastoralism and agro- pastoralism are the two major livelihood ways practiced in the region. The population of the region is estimated to be about 1.4 million of which 90% are pastoralists and 10% agro- pastoral. The altitude of the region ranges from 120m below sea level to 1500m above sea level. Temperatures vary from 200C in higher elevations to 480C in lower elevations. Rainfall is bi-modal throughout the region with a mean annual rainfall below 500 mm in the semi-arid western escarpments and decreasing to 150 mm in the arid zones to the east .The study was conducted in three districts selected from three zones, namely: Asayita district of Awsi resu zone, Aba’ala district of Kilebeti resu zone and Gewanie district of Gebi resu zone.
2.2. Target Population for the Study
The target populations for this study were livestock owners (herders and traditional healers) and animal health practitioners.
2.3. Study Design and Sampling Methods
The study design was cross-sectional type. Regarding sampling, three zones from the region and one district each from three zones were selected purposively based on expected plant coverage. Pastoralist Association (PA) was the lowest administrative unit within the district that was considered during the study. Accordingly, four PAs from each district were conveniently selected based on variety plant coverage and availability of traditional healers and individuals with good experience and knowledge of plant poisoning. All volunteer traditional healers selected based on recommendation from elders and other concerned bodies, and herders and animal health practitioners with good knowledge of plant poisoning were considered for the study. A total of 245 individuals were interviewed for the questionnaire survey and among these 35 individuals were used for the plant collection and identification based on their knowledge and interest to participate in the study.
2.4. Data Collection
2.4.1. Questionnaire Survey
Questionnaire survey was carried out by interviewing 245 voluntary animal owners, traditional animal healers and animal health practitioners. The questionnaire was used to collect information related to types of livestock poisoning due to poisonous plants; local name of poisonous plants; poisonous parts of the plant (seed, bark, leaves, etc), poisonous growth stage and state of poisoning; seasons of abundance of the poisonous plant; ways of exposure, amount to cause poisoning, and poisonous effects produced on exposure; agro-ecological and habitat of the poisonous plant and species of livestock mostly affected from the poisoning.
2.4.2. Key Informants Interview
From the total 245 individuals, an in-depth interview was conducted with 35 traditional healers and animal health practitioners in each selected districts who has helped in collecting and identifying the poisonous plants from the field in the region. The selection of these key informants was based on their knowledge and experience in the issue with the help of administrators, veterinarians and elders in the areas.
2.4.3. Sample Collection
Appropriate sample of plant parts was collected from surrounding rangeland of study areas with the key informants who knows the local name of the plants. The samples collected from the rangeland were compressed and preserved in laboratory according to Queensland Herbarium plant specimen collection and preserving manual  and Biology department of Samara University was contacted for taxonomic identification.
2.5. Data Management and Analysis
The information that was gathered through questionnaire survey on suspected and complained poisonous plants to livestock was coded and entered to Microsoft Excel 2007 spread sheet. SPSS version 20 was used for the analysis. Descriptive statistics was used to calculate frequency and the percentage of the respondents.
In the present study, from the total respondents (245), about 70.2% (172) of the interviewee were livestock owners and 15.5% (38) and 14.3% (35) were animal health practitioners and traditional healers, respectively. The majorly described predisposing factors for the occurrence of plant poisoning were feed shortage, nutritional deficiency and excessive consumption. The common poisoning seasons indicated were at the end of rainy season (August to September) and during drought time (February to May) but at the beginning of the rainy Season (June to July) was low (Table 1).
According to the present study, a total of 21 plants were identified and documented to have a poisonous effect on livestock. The poisonous plants frequently complained by the respondents were Capparis tomentosa, Prosopis juliflora, Parthenium hysterophorus, Lantana camara, Acacia absynica, Sorghum bicolar, Datura stramonium, Plantago lanceolata, Grass species, Bracken fern (Pteridium aquilinum) and Solanum incanum (Figs. 1-8). The major plant parts that caused poisoning were leaves. This study also revealed that bloating and other GIT disturbances, salivation, bloody urine and inappetence were among the frequently manifested signs by poisoned livestock. Moreover, this study showed that caprine and bovine followed by camels and ovine were the most frequently poisoned animals (Table 2).
The poisonous plants with higher botanical frequency complained by respondents were Capparis tomentosa (156) and Prosopis juliflora (133). The clinical sign with leading veterinary frequency was bloating. Moreover, majority of the poisonous plants mainly occur at the rainy season and causes poisoning after repeated exposure (Table 3).
Table 1. Summary of responses on risk factors associated with plant poisoning.
|Variables||No. of Respondents||Percentage (%)*|
|Common poisoning season|
|Beginning of rainy season||89||36.3|
|End of rainy season||245||100|
|Source of poisoning plants|
|Predisposing factors for consumption|
|Scientific Name||Local Name (Qafaraf)||Poisonous Part||Clinical Signs||Species Affected||Source|
|Bloating, Death||Camel||Both wild and domestic|
|Bloating, Lower jaw dislocation||Camel, ovine, caprine, bovine||Both wild and domestic|
|Parthenium hysterophorus||–||Whole||Anuria, hematuria||Camel, ovine, caprine, bovine||Both wild and domestic|
|Lantana camara||–||Leaf||Photosensitization, bloody urine||Camel, bovine, caprine||Wild|
|Sorghum bicolar||Basinga||Seedling||Bloating, death||Bovine, caprine, ovine||Domestic|
|Grass species||Ayiso||Whole||Bloating, inappetance||Bovine, ovine||Both wild and domestic|
|Bracken fern (Pteridium aquilinum)||–||Leaf||Bloody urine||Camel, bovine, caprine||Wild|
|Medicago burweed||–||Whole||Bloating||Bovine, ovine||Wild|
|Snowdonia polystachia||–||Whole||Bloating, diarrhea||Camel, bovine, caprine||Domestic|
|Prunus Africana||–||Leaf||Bloating, salivation||Bovine, caprine||Wild|
|Diarrhea, lacrimation, incoordination, inappetance||Camel, bovine, caprine, ovine||Wild|
|Diarrhea, depression||All animals||Both wild and domestic|
|–||Whole||Bloating, anuria||Bovine, ovine||Wild|
|Amaranthus spp.||–||Leaf||Bloating, Bloody urine||Camel, bovine, caprine, ovine||Wild|
|Acacia absynica||Goronta||Leaf||Bloating||Bovine, caprine||Wild|
|Depression, erection of Hair,
|Maytenus senegalensis||–||Leaf||Bloody urine||Camel, Bovine caprine, ovine||Wild|
|Scientific Names||Local Name (Qafaraf)||Botanical Frequency||Veterinary Frequency||Exposure Level||Season|
|Capparis tomentosa||Andela||156||Bloating (136), Death (20)||Single||Any time|
|Prosopis juliflora||Datihara||133||Bloalting (22), Lower jaw dislocation (111)||Repeated||Winter|
|Parthenium hysterophorus||-||124||Anuria (34), hematuria (90)||Repeated||Summer, autumn|
|Lantana camara||-||56||Photosensitization (41), bloody urine (l5)||Repeated||Summer|
|Sorghum bicolar||Basinga||117||Bloating (85), death (32)||Single||Summer, autumn|
|Grass species||Ayiso||141||Bloating (122), inappetance (19)||Repeated||Summer|
|Bracken fern (Pteridium aquilinum)||21||Bloody urine (21)||Repeated||Winter|
|Medicago burweed||13||Bloating (13)||Single||Summer|
|Snowdonia polystachia||15||Bloating (6), diarrhea (9)||Single||Summer|
|Prunus Africana||8||Bloating (3), salivation (5)||Repeated||Summer|
|Solanum incanum||6||Diarrhea (4), incoordination (2)||Single||Summer|
|2||Diarrhea (1), depression (1)||Single||Summer|
|3||Bloating (2), anuria (1)||Repeated||Any time|
|Amaranthus spp.||2||Bloating (1), bloody urine (1)||Repeated||Summer|
|Acacia absynica||Goronta||34||Bloating (34)||Repeated||Any time|
|4||Depression (1), erection of hair (1),
|Maytenus senegalensis||1||Bloody urine (1)||Single||Any time|
|Characteristics of Variables||Frequency||Percentage (%)|
|Leaf and Seed pod||2||9.5|
|Leaf and fruit||1||4.8|
|Fruit and Seed||3||14.3|
|Summer and autumn||2||9.5|
|Lower jaw dislocation||1||4.8|
|Erection of hair||1||4.8|
Poisonous Plants Collected from the study areas.
|Fig. (1). Picture of Capparis Tomentosa (‘Andela’)|
|Fig. (2). Picture of ‘Asihara’|
|Fig. (3). Picture of ‘Boboe’ita’|
|Fig. (4). Picture of Solanum incanum|
|Fig. (5). Picture of Parthenium hysterophorus|
|Fig. (6). Picture of Lantana Camara|
|Fig. (7). Picture of ‘Adihara'|
|Fig. (8). Picture of Prosopis juliflora (‘Datihara’)|
Animal poisoning due to plants constitutes one of the most important health problems to livestock in countries with extensive production system . In this study, the respondents have showed that livestock health disorders due to phytopoisoning cause a significant morbidity and mortality in animals in their areas.
The major predisposing factors for the occurrence of plant poisoning in the study areas were feed shortage, nutritional deficiency and excessive consumption. Afar region is one of the pastoral areas of Ethiopia with lower rainfall and limited plant coverage but rich in livestock production potential. This condition showed that there is long dry period and feed shortage in the region. Hence, due to feed shortage, animals are enforced to feed on poisonous perennial shrubs and bushes surviving the environment which are known to contain poisonous metabolites. In addition, there is a sudden consumption of new plants while migrating and excessive consumption of plants grown following short rainy season which contributed to phytopoisoning. Accordingly, the common poisoning seasons complained were at the end of rainy season (August-September) and during drought time (February-May). This finding is in agreement with the similar reports from Wollega, Ethiopia [14, 15].
According to this study, a total of 21 plants were identified and documented to have a poisonous effect on livestock. The poisonous plants frequently described by the respondents were Capparis tomentosa, Prosopis juliflora, Parthenium hysterophorus, Lantana camara, Acacia abyssnica, Sorghum bicolar, Datura stramonium, Plantago lanceolata, Grass species such as Panicum species, Bracken fern (Pteridium aquilinum) and Solanum incanum. Reports from Adama, Ethiopia  and from Wolllega, Ethiopia [14, 15] have documented Parthenium hysterophorus, Lantana camara, Sorghum bicolar, Datura stramonium, Plantago lanceolata, Panicum grass species and Bracken fern (Pteridium aquilinum) as the most frequently implicated poisonous plants which are in agreement with the current finding.
In addition, the importance of Snowdenia polystarchia, and Sorghum bicolar as causes of livestock poisoning have been reported . Similarily, Lantana camara causes similar effect in Columbia  and in Swaziland . Bracken fern is also widely distributed in many parts of the world including Ethiopia. Its existence and importance as a cause of bloody urine has been previously shown in different regions  and it has also been reported in South Africa . Various studies conducted on this issue indicated that poisonous plants may grow together with forage plants; therefore, readily accessible to grazing animals. Under normal conditions only a few poisonous plants can be considered sufficiently palatable. But during shortage of pasture and forage animals may be forced to browse these poisonous plants [16, 22, 23].
The respondents of this study showed that when camels and small ruminants feed on ‘Andela’ (Capparis tomentosa) the leaf causes bloating but its seed pod is fatal to both animals. A leaf of ‘Adihara’ causes bloating in goats but it is a good feed to other large animals. The leaf and fruit of ‘Asihara’ causes bloating in animals especially camels and goats but after repeated exposure it becomes edible without serious effects. It grows at the end of rainy season or any time in irrigation fields. A leaf of ‘Bobe’eita’ is fatal to goats but it is a common feed to camels and it is commonly found in high hills. The seedling stage of ‘Basinga’ (Sorghum bicolar) can cause bloating in all animals but it may kill animals if it is overtaken at the same time. A leaf of ‘Datihara’ (Prosopis juliflora) is not palatable by animals due to its repellant nature but during drought times animals may be enforced to consume some as it is ever green and it causes bloating. Although its seed pod is palatable by animals, it can cause lower jaw dislocation when it is consumed after it is dropped and decayed in the ground and when it is not consumed together with other feed types . Any type of grass especially Panicum grass species emerging at the beginning of rainy season have the potential to cause bloating and/or diarrhea as the animals consume much of it at a time following long dry periods.
The major plant parts that caused poisoning were leaves as these parts are easily accessible and repeatedly fed by animals. This study also revealed that bloating and other GIT disturbances, salivation, bloody urine and inappetance were among the frequently manifested signs by poisoned livestock. This finding is in agreement with the reports in Wollega, Ethiopia [14, 15]. Furthermore, this study showed that caprine and bovine followed by camels and ovine were the most frequently poisoned animals which did not agree with the reports from Wollega. This could be due to the difference in livestock species abundance in which small ruminants and camels constitutes majority of livestock population in the current study area.
The clinical sign with leading veterinary frequency was bloating as the poisonous plants primarily affect the digestive system of animals. Moreover, majority of the poisonous plants mainly occur on the rainy season because following the rainfall a lot of plants will grow up and causes poisoning after repeated exposure. This finding is in line with the findings in Wollega, Ethiopia [14, 15]. The poisonous plants with higher botanical frequency identified by respondents were Caparis tomentosa and Prosopis juliflora which differed from the above reports because of the difference in climatic conditions and plant coverage in the current study areas.
This study identified and documented a total of 21 plants having a poisonous effect on livestock. The poisonous plants with higher botanical frequency were Capparis tomentosa and Prosopis juliflora. Feed shortage, nutritional deficiency and excessive consumption were the major predisposing factors for the occurrence of plant poisoning. The common poisoning seasons were at the end of rainy season and during drought time. This study also revealed that bloating and other GIT disturbances were among the frequently manifested signs by poisoned livestock. Moreover, this study showed that caprine and bovine followed by camels and ovine were the most frequently poisoned animals. Hence, phytopoisoning is commonly occurring and challenging health of livestock in the area. Therefore, proper range management should be practiced to decrease the danger of plant poisoning to animals and all concerned bodies should collaborate on pasture and water development programs to minimize the risk of enforced consumption of livestock on poisonous plants due to feed shortage.
ETHICS APPROVAL AND CONSENT TO PARTICIPATE
RESEARCH INVOLVING PLANTS
All the experimental research on plants was in accordance with "B. Tony, “Collection and preserving plant specimens”, a manual. Queensland Herbarium, Department of Science, Information Technology and Innovation, 2nd ed, Brisbane Botanic Gardens Mt Coot-tha, Mt Coo-tha road, Toowong Brisbane QLD 4066, 2016".
CONSENT FOR PUBLICATION
AVAILABILITY OF DATA AND MATERIALS
The research was done by the fund totally granted from Samara University (One of the National University found in Afar Regional State of Ethiopia) by the grant Reference Number: SU/RCSVP/32/2016.
CONFLICT OF INTEREST
The author declares no conflict of interest, financial or otherwise.
The author would like to acknowledge Samara University for the funding and Agriculture office of the study districts of Afar region and to traditional healers, livestock owners and animal health assistants of all study districts for their support during sample collection.